. Carnegie Institution of Washington publication. STEWART'S DISEASE OF SWEET CORN (MAIZE). 91 due to the presence of an oxidizable substance in some bundles and its absence in others, or simply to the fact that more air (oxygen) has been able to enter some vessels than others, the dark stain depending on an oxidation. A similar phenomenon occurs in the sugar-cane attacked by Cobb's disease. Reddeningof the vascular bundles or white striping of the leaves (a sign met with in sugar-cane attacked by Bacterium vasciilanim) does not occur in this disease. The slime of the disease also sometimes occ
. Carnegie Institution of Washington publication. STEWART'S DISEASE OF SWEET CORN (MAIZE). 91 due to the presence of an oxidizable substance in some bundles and its absence in others, or simply to the fact that more air (oxygen) has been able to enter some vessels than others, the dark stain depending on an oxidation. A similar phenomenon occurs in the sugar-cane attacked by Cobb's disease. Reddeningof the vascular bundles or white striping of the leaves (a sign met with in sugar-cane attacked by Bacterium vasciilanim) does not occur in this disease. The slime of the disease also sometimes occurs in roots which appear sound exter- nally. This is especially true of parts of roots near their union with badly diseased stems. As a rule the roots are not badly diseased. The writer has observed no tendency of the yellow slime to break through and ooze on the surface of the plant, except from the inner face of the inner husks, where such oozing is quite common, and more rarely from the inner face of the leaf-sheath. Stewart found this yellow slime oozing over the kernels in plants killed by the disease. The main axis of the maize plant has a firm siliceous covering, and even at the base of the stem, which is usually the first part of the stem to become diseased, there is a thin layer of unbroken, hard, sound tissue separating the sick interior from the air and soil, even when the plants have been diseased for some time (10 weeks or more) and the vascular bundles are occu- pied by the bacteria the whole length of the stem. This is true even when the lower nodes and internodes have become quite brown and gummy and most of the leaves have succumbed to the disease. Very rarely, in the middle part of the stem, in badly diseased, soft plants, ooze may come from some restricted spots on the internodes. As the disease progresses, the bac- terial slime is sometimes found in the parenchyma between the bundles either as water-soaked patches or as bright yellow spots, but large caviti
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